This invention relates to enediyne quinone imines, compounds useful for the treatment of cancer, and to methods of preparing and using them.
The novel enediyne antibiotic dynemicin A (1) (Konishi, M.; Ohkuma, H.; Matsumoto, K.; Tsuno, T.; Kamei, H.; Miyaki, T.; Oki, T.; Kawaguchi, H.; Van Duyne, G. D.; Clardy, J. J. Antibiot. 1989, 42, 1449. Konishi, M.; Ohkuma, H.; Tsuno, T.; Oki, T.; VanDuyne, G. D.; Clardy, J. J. Am. Chem. Soc. 1990, 112, 3715) has stimulated the pursuit of DNA cleavage studies (Sugiura, Y.; Shiraki, T.; Konishi, M.; Oki, T. Proc. Nat. Acad. Sci. U.S.A. 1990,87, 3831), the design of new pro-drug constructs and the development of novel methodology directed at total synthesis. Nicolaou, K. C.; Dai, W. -M. Angew. Chem. Int. Ed. Engl. 1991, 30 1387; Taunton, J.; Wood, J. L.; Schreiber, S. L. J. Am. Chem. Soc. 1993, 115, 10378. The prevailing assumption (Semmelhack, M. F.; Gallagher, J.; Cohen, D. Tetrahedron Lett. 1990, 31, 1521; Sugiura, Y.; Shiraki, T.; Konishi, M.; Oki, T. Proc. Nat. Acad. Sci. U.S.A. 1990 87, 3831) concerning the ignition mechanism for the drug to operate as a diyl precursor presupposes reduction of the quinone ring to the hydroquinone state.
In this way the "lone pair" on nitrogen is unleashed to participate in mediating solvent attack on the epoxide (Scheme 1, see arrows). The opening of this epoxide is a critical prophase in fostering the Bergman (enediyne.fwdarw. 1,4-diyl) transformation. Jones, R. R.; Bergman, R. G. J. Am. Chem. SOC. 1972, 94, 660. Bergman, R. G.; Acc. Chem. Res. 1973, 6, 25. The cytotoxicity of enediyne antibiotics is thought to arise from the DNA cutting tendency of diyl 2 or its quinone counterpart. Sugiura, Y.; Shiraki, T.; Konishi, M.; Oki, T. Proc. Nat. Acad. Sci. U.S.A. 1990, 87, 3831. The dihydroxy naphthaquinone sector presumably provides noncovalent intercalative contacts for directing the drug to its oligonucleotide target. Sugiura, Y.; Shiraki, T.; Konishi, M.; Oki, T. Proc. Nat. Acad. Sci. U.S.A. 1990, 87 3831; Arcamone, F. in Doxorubicin Anticancer Antibiotics, Academic, New York, 1981; Neidle, S.; Pearl, L. H.; Skelly, J. V. Biochem. J. 1987, 243, 1-13; Wang, A.; Ughetto, G.; Quigley, G.; Rich, A. Biochemistry 1987, 26, 1152. The present invention provides new analogues of enediyne antibiotics and methods of preparing and using them, and offers a potentially important advance for cancer chemotherapy.